Hola! From a Spanish Speaking Drawing Arm

[Acorv] wrote in to tell us about his latest hack, a robotic arm that writes with a marker. In the video after the break, the arm is set to copy whatever someone writes in a touchpad. As you might guess from this video, the hack is written up in Spanish, but it’s nothing your favorite translator can’t handle if you don’t speak the language.

This robot it the result of improvements on his first drawing arm ‘bot featured here. The basic kinematics stayed the same in the arm’s second iteration, but the resolution was greatly improved by using belts to achieve a gear reduction. The second build also features mechanical reinforcement with an Erector-set style building set known as [Mekanex].

A simple hobby servo moves the marker up or down, and control is achieved through, you guessed it, an Arduino with a motor shield! Although from a different time, the way this arm is used is reminiscent of a mechanical writing automaton from long ago.

It’s a shame the video is hoted on Vimeo, their servers are always overloaded and they don’t have a good world distribution – so if you’re outside the US it takes forever to load even the shortest of videos.

Regardless of that, it’s a cool project. It seems pretty accurate which is a big plus on other similar projects I’ve seen.

Interesting, I’ve always found Vimeo videos to load a lot faster than youtube. Also I never see the half way buffer using vimeo that I often get with youtube (where the video will buffer up to a certain point and then stop buffering for no apparent reason)

The limited buffering is almost certainly a bandwidth saving approach. I certainly don’t watch the entirety of most vids I start watching… That said, I assume the amount of buffered footage is set based on the download rate such that you can watch continuously. But I’m sure that’s often not foolproof.

FLV/H.264 videos (itag 34, 35) after a short burst are throttled to x1.25 max. == fail.
WebM/VP8 format videos (itag 43, 44, 45) are not explicitely limited.
May use html5 instead of flash to watch them as they want to force people to swicth.

It reminds me of the auto signature machine i saw in quite a few senate offices in Washington D.C. a similar concept but in a mechanical 70’s era technology with a pin that followed a plate and duplicated the signature on paper with a pen. Surely with the way government spending is these were far more expensive than this far more capable one.